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Functional Recognition by CD8+ T Cells of Epitopes with Amino Acid Variations Outside Known MHC Anchor or T Cell Receptor Recognition Residues. Int J Mol Sci 2020; 21:ijms21134700. [PMID: 32630213 PMCID: PMC7369715 DOI: 10.3390/ijms21134700] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2020] [Revised: 06/23/2020] [Accepted: 06/29/2020] [Indexed: 11/22/2022] Open
Abstract
Peptide-based vaccines can be safer and more cost effective than whole organism vaccines. Previous studies have shown that inorganic polystyrene nanoparticles (PSNPs) covalently conjugated to the minimal immunodominant peptide epitope from murine liver stage malaria (SYIPSAEKI) induced potent CD8+ T cell responses. Many pathogens, including malaria, have polymorphic T cell epitope regions. Amino acid changes in positions that are contact residues for the T cell receptor (TCR) often alter the specific cross-reactivity induced by the peptide antigen, and it is largely assumed that changes outside of these residues have little impact. Herein, each amino acid residue (except major histocompatibility complex (MHC) anchors) was systematically changed to an alanine. Peptide epitopes with altered amino acids outside T cell contact residues were still recognized by T cells induced by PSNPs-SYIPSAEKI (KI) vaccines, albeit at lower levels, except for the variant SYIPSAAKI (A7). PSNPs-SYIPSAAKI vaccines further elicited high responses to the index KI peptide. None of the epitopes displayed altered peptide ligand (APL) antagonism in vitro, and re-stimulating SYIPSAEKI and SYIPSAAKI together synergistically enhanced IFN-γ production by the T cells. These results show epitope variation in non-TCR recognition residues can have effects on T cell reactivity, suggesting that such natural variation may also be driven by immune pressure. Additionally, when re-modelling peptides to enhance the cross-reactivity of vaccines, both TCR recognition and non-recognition residues should be considered.
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Patarroyo MA, Arévalo-Pinzón G, Moreno-Pérez DA. From a basic to a functional approach for developing a blood stage vaccine against Plasmodium vivax. Expert Rev Vaccines 2020; 19:195-207. [PMID: 32077349 DOI: 10.1080/14760584.2020.1733421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Introduction: Numerous challenges have hampered developing an anti-malarial vaccine against the most widespread malarial parasite worldwide: Plasmodium vivax. Despite the progress achieved in studying proteins in short-term in vitro culture or in experimental models, there is still no clear method for defining which antigens or their regions should be prioritized for including them in a vaccine.Areas covered: The methods used by research groups so far which have focused on the functional analysis of P. vivax blood stage antigens have been reviewed here. A logical strategy orientated toward resolving two of the most commonly occurring problems in designing vaccines against this species has thus been proposed (i.e. the search for candidates and evaluating/ascertaining their functional role in the invasion of such molecules).Expert commentary: Advances in knowledge regarding P. vivax biology have been extremely slow. Only two key receptor-ligand interactions concerning merozoite entry to reticulocytes have been reported during the last 20 years: PvDBP1-DARC and PvRBP2b-CD71. Despite increasing knowledge about the parasite's intimate preference for its host cells, it has yet to be determined which regions of the merozoite molecules characterized to date meet the requirement of inducing protective immune responses effectively blocking heterologous parasite entry to human cells.
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Affiliation(s)
- Manuel Alfonso Patarroyo
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá D.C., Colombia.,School of Medicine and Health Sciences, Universidad del Rosario, Bogotá D.C., Colombia
| | - Gabriela Arévalo-Pinzón
- School of Medicine and Health Sciences, Universidad del Rosario, Bogotá D.C., Colombia.,Receptor-Ligand Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá D.C., Colombia
| | - Darwin A Moreno-Pérez
- Molecular Biology and Immunology Department, Fundación Instituto de Inmunología de Colombia (FIDIC), Bogotá D.C., Colombia.,School of Medicine and Health Sciences, Universidad del Rosario, Bogotá D.C., Colombia.,Livestock Sciences Faculty, Universidad de Ciencias Aplicadas Y Ambientales (U.D.C.A), Bogotá DC, Colombia
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3
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Gbedande K, Carpio VH, Stephens R. Using two phases of the CD4 T cell response to blood-stage murine malaria to understand regulation of systemic immunity and placental pathology in Plasmodium falciparum infection. Immunol Rev 2020; 293:88-114. [PMID: 31903675 PMCID: PMC7540220 DOI: 10.1111/imr.12835] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 12/08/2019] [Accepted: 12/09/2019] [Indexed: 02/06/2023]
Abstract
Plasmodium falciparum infection and malaria remain a risk for millions of children and pregnant women. Here, we seek to integrate knowledge of mouse and human T helper cell (Th) responses to blood-stage Plasmodium infection to understand their contribution to protection and pathology. Although there is no complete Th subset differentiation, the adaptive response occurs in two phases in non-lethal rodent Plasmodium infection, coordinated by Th cells. In short, cellular immune responses limit the peak of parasitemia during the first phase; in the second phase, humoral immunity from T cell-dependent germinal centers is critical for complete clearance of rapidly changing parasite. A strong IFN-γ response kills parasite, but an excess of TNF compared with regulatory cytokines (IL-10, TGF-β) can cause immunopathology. This common pathway for pathology is associated with anemia, cerebral malaria, and placental malaria. These two phases can be used to both understand how the host responds to rapidly growing parasite and how it attempts to control immunopathology and variation. This dual nature of T cell immunity to Plasmodium is discussed, with particular reference to the protective nature of the continuous generation of effector T cells, and the unique contribution of effector memory T cells.
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Affiliation(s)
- Komi Gbedande
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas
| | - Victor H Carpio
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas
| | - Robin Stephens
- Division of Infectious Diseases, Department of Internal Medicine, University of Texas Medical Branch, Galveston, Texas
- Department of Microbiology and Immunology, University of Texas Medical Branch, Galveston, Texas
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4
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Tran TM, Crompton PD. Decoding the complexities of human malaria through systems immunology. Immunol Rev 2019; 293:144-162. [PMID: 31680289 DOI: 10.1111/imr.12817] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2019] [Revised: 09/27/2019] [Accepted: 09/30/2019] [Indexed: 12/18/2022]
Abstract
The complexity of the Plasmodium parasite and its life cycle poses a challenge to our understanding of the host immune response against malaria. Studying human immune responses during natural and experimental Plasmodium infections can enhance our understanding of malaria-protective immunity and inform the design of disease-modifying adjunctive therapies and next-generation malaria vaccines. Systems immunology can complement conventional approaches to facilitate our understanding of the complex immune response to the highly dynamic malaria parasite. In this review, recent studies that used systems-based approaches to evaluate human immune responses during natural and experimental Plasmodium falciparum and Plasmodium vivax infections as well as during immunization with candidate malaria vaccines are summarized and related to each other. The potential for next-generation technologies to address the current limitations of systems-based studies of human malaria are discussed.
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Affiliation(s)
- Tuan M Tran
- Division of Infectious Diseases, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN, USA.,Ryan White Center for Pediatric Infectious Disease and Global Health, Department of Pediatrics, Indiana University School of Medicine, Indianapolis, IN, USA.,Department of Microbiology and Immunology, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Peter D Crompton
- Malaria Infection Biology and Immunity Section, Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD, USA
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Wilson KL, Flanagan KL, Prakash MD, Plebanski M. Malaria vaccines in the eradication era: current status and future perspectives. Expert Rev Vaccines 2019; 18:133-151. [PMID: 30601095 DOI: 10.1080/14760584.2019.1561289] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
INTRODUCTION The challenge to eradicate malaria is an enormous task that will not be achieved by current control measures, thus an efficacious and long-lasting malaria vaccine is required. The licensing of RTS, S/AS01 is a step forward in providing some protection, but a malaria vaccine that protects across multiple transmission seasons is still needed. To achieve this, inducing beneficial immune responses while minimising deleterious non-targeted effects will be essential. AREAS COVERED This article discusses the current challenges and advances in malaria vaccine development and reviews recent human clinical trials for each stage of infection. Pubmed and ScienceDirect were searched, focusing on cell mediated immunity and how T cell subsets might be targeted in future vaccines using novel adjuvants and emerging vaccine technologies. EXPERT COMMENTARY Despite decades of research there is no highly effective licensed malaria vaccine. However, there is cause for optimism as new adjuvants and vaccine systems emerge, and our understanding of correlates of protection increases, especially regarding cellular immunity. The new field of heterologous (non-specific) effects of vaccines also highlights the broader consequences of immunization. Importantly, the WHO led Malaria Vaccine Technology Roadmap illustrates that there is a political will among the global health community to make it happen.
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Affiliation(s)
- K L Wilson
- a Department of Immunology and Pathology, Faculty of Medicine, Nursing and Health Sciences , Monash University , Melbourne , Australia.,b School of Health and Biomedical Sciences , RMIT University , Bundoora , Australia
| | - K L Flanagan
- a Department of Immunology and Pathology, Faculty of Medicine, Nursing and Health Sciences , Monash University , Melbourne , Australia.,b School of Health and Biomedical Sciences , RMIT University , Bundoora , Australia.,c School of Medicine, Faculty of Health Sciences , University of Tasmania , Launceston , Australia
| | - M D Prakash
- b School of Health and Biomedical Sciences , RMIT University , Bundoora , Australia
| | - M Plebanski
- b School of Health and Biomedical Sciences , RMIT University , Bundoora , Australia
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Xiang SD, Wilson KL, Goubier A, Heyerick A, Plebanski M. Design of Peptide-Based Nanovaccines Targeting Leading Antigens From Gynecological Cancers to Induce HLA-A2.1 Restricted CD8 + T Cell Responses. Front Immunol 2018; 9:2968. [PMID: 30631324 PMCID: PMC6315164 DOI: 10.3389/fimmu.2018.02968] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2018] [Accepted: 12/03/2018] [Indexed: 01/02/2023] Open
Abstract
Gynecological cancers are a leading cause of mortality in women. CD8+ T cell immunity largely correlates with enhanced survival, whereas inflammation is associated with poor prognosis. Previous studies have shown polystyrene nanoparticles (PSNPs) are biocompatible, do not induce inflammation and when used as vaccine carriers for model peptides induce CD8+ T cell responses. Herein we test the immunogenicity of 24 different peptides, from three leading vaccine target proteins in gynecological cancers: the E7 protein of human papilloma virus (HPV); Wilms Tumor antigen 1 (WT1) and survivin (SV), in PSNP conjugate vaccines. Of relevance to vaccine development was the finding that a minimal CD8+ T cell peptide epitope from HPV was not able to induce HLA-A2.1 specific CD8+ T cell responses in transgenic humanized mice using conventional adjuvants such as CpG, but was nevertheless able to generate strong immunity when delivered as part of a specific longer peptide conjugated to PSNPs vaccines. Conversely, in most cases, when the minimal CD8+ T cell epitopes were able to induce immune responses (with WT1 or SV super agonists) in CpG, they also induced responses when conjugated to PSNPs. In this case, extending the sequence around the CD8+ T cell epitope, using the natural protein context, or engineering linker sequences proposed to enhance antigen processing, had minimal effects in enhancing or changing the cross-reactivity pattern induced by the super agonists. Nanoparticle approaches, such as PSNPs, therefore may offer an alternative vaccination strategy when conventional adjuvants are unable to elicit the desired CD8+ T cell specificity. The findings herein also offer sequence specific insights into peptide vaccine design for nanoparticle-based vaccine carriers.
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Affiliation(s)
- Sue D Xiang
- Department of Immunology, Faculty of Medicine, Nursing and Health Sciences, Central Clinical School, Monash University, Melbourne, VIC, Australia.,PX Biosolutions Pty Ltd., South Melbourne, VIC, Australia.,Ovarian Cancer Biomarker Laboratory, Hudson Institute of Medical Research, Clayton, VIC, Australia
| | - Kirsty L Wilson
- Department of Immunology, Faculty of Medicine, Nursing and Health Sciences, Central Clinical School, Monash University, Melbourne, VIC, Australia
| | - Anne Goubier
- PX Biosolutions Pty Ltd., South Melbourne, VIC, Australia
| | - Arne Heyerick
- PX Biosolutions Pty Ltd., South Melbourne, VIC, Australia
| | - Magdalena Plebanski
- Department of Immunology, Faculty of Medicine, Nursing and Health Sciences, Central Clinical School, Monash University, Melbourne, VIC, Australia.,PX Biosolutions Pty Ltd., South Melbourne, VIC, Australia.,School of Health and Biomedical Sciences, RMIT University, Bundoora, VIC, Australia
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Homan EJ, Bremel RD. A Role for Epitope Networking in Immunomodulation by Helminths. Front Immunol 2018; 9:1763. [PMID: 30108588 PMCID: PMC6079203 DOI: 10.3389/fimmu.2018.01763] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2018] [Accepted: 07/17/2018] [Indexed: 12/19/2022] Open
Abstract
Helminth infections, by nematodes, trematodes, or cestodes, can lead to the modulation of host immune responses. This allows long-duration parasite infections and also impacts responses to co-infections. Surface, secreted, excreted, and shed proteins are thought to play a major role in modulation. A commonly reported feature of such immune modulation is the role of T regulatory (Treg) cells and IL-10. Efforts to identify helminth proteins, which cause immunomodulation, have identified candidates but not provided clarity as to a uniform mechanism driving modulation. In this study, we applied a bioinformatics systems approach, allowing us to analyze predicted T-cell epitopes of 17 helminth species and the responses to their surface proteins. In addition to major histocompatibility complex (MHC) binding, we analyzed amino acid motifs that would be recognized by T-cell receptors [T-cell-exposed motifs (TCEMs)]. All the helminth species examined have, within their surface proteins, peptides, which combine very common TCEMs with predicted high affinity binding to many human MHC alleles. This combination of features would result in large cognate T cell and a high probability of eliciting Treg responses. The TCEMs, which determine recognition by responding T-cell clones, are shared to a high degree between helminth species and with Plasmodium falciparum and Mycobacterium tuberculosis, both common co-infecting organisms. The implication of our observations is not only that Treg cells play a significant role in helminth-induced immune modulation but also that the epitope specificities of Treg responses are shared across species and genera of helminth. Hence, the immune response to a given helminth cannot be considered in isolation but rather forms part of an epitope ecosystem, or microenvironment, in which potentially immunosuppressive peptides in the helminth network via their common T-cell receptor recognition signals with T-cell epitopes in self proteins, microbiome, other helminths, and taxonomically unrelated pathogens. Such a systems approach provides a high-level view of the antigen-immune system signaling dynamics that may bias a host's immune response to helminth infections toward immune modulation. It may indicate how helminths have evolved to select for peptides that favor long-term parasite host coexistence.
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Abstract
Safe and efficacious vaccines are arguably the most successful medical interventions of all time. Yet the ongoing discovery of new pathogens, along with emergence of antibiotic-resistant pathogens and a burgeoning population at risk of such infections, imposes unprecedented public health challenges. To meet these challenges, innovative strategies to discover and develop new or improved anti-infective vaccines are necessary. These approaches must intersect the most meaningful insights into protective immunity and advanced technologies with capabilities to deliver immunogens for optimal immune protection. This goal is considered through several recent advances in host-pathogen relationships, conceptual strides in vaccinology, and emerging technologies. Given a clear and growing risk of pandemic disease should the threat of infection go unmet, developing vaccines that optimize protective immunity against high-priority and antibiotic-resistant pathogens represents an urgent and unifying imperative.
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Affiliation(s)
- Michael R Yeaman
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California 90024.,Division of Molecular Medicine, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California 90509; .,Division of Infectious Diseases, Department of Medicine, Harbor-UCLA Medical Center, Torrance, California 90509.,Los Angeles Biomedical Research Institute, Torrance, California 90502
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9
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Ntege EH, Takashima E, Morita M, Nagaoka H, Ishino T, Tsuboi T. Blood-stage malaria vaccines: post-genome strategies for the identification of novel vaccine candidates. Expert Rev Vaccines 2017; 16:769-779. [PMID: 28604122 DOI: 10.1080/14760584.2017.1341317] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
Abstract
INTRODUCTION An efficacious malaria vaccine is necessary to advance the current control measures towards malaria elimination. To-date, only RTS,S/AS01, a leading pre-erythrocytic stage vaccine completed phase 3 trials, but with an efficacy of 28-36% in children, and 18-26% in infants, that waned over time. Blood-stage malaria vaccines protect against disease, and are considered effective targets for the logical design of next generation vaccines to improve the RTS,S field efficacy. Therefore, novel blood-stage vaccine candidate discovery efforts are critical, albeit with several challenges including, high polymorphisms in vaccine antigens, poor understanding of targets of naturally protective immunity, and difficulties in the expression of high AT-rich plasmodial proteins. Areas covered: PubMed ( www.ncbi.nlm.nih.gov/pubmed ) was searched to review the progress and future prospects of malaria vaccine research and development. We focused on post-genome vaccine candidate discovery, malaria vaccine development, sequence diversity, pre-clinical and clinical trials. Expert commentary: Post-genome high-throughput technologies using wheat germ cell-free protein synthesis technology and immuno-profiling with sera from malaria patients with clearly defined outcomes are highlighted to overcome current challenges of malaria vaccine candidate discovery.
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Affiliation(s)
- Edward H Ntege
- a Division of Malaria Research , Proteo-Science Center, Ehime University , Matsuyama , Ehime , Japan
| | - Eizo Takashima
- a Division of Malaria Research , Proteo-Science Center, Ehime University , Matsuyama , Ehime , Japan
| | - Masayuki Morita
- a Division of Malaria Research , Proteo-Science Center, Ehime University , Matsuyama , Ehime , Japan
| | - Hikaru Nagaoka
- a Division of Malaria Research , Proteo-Science Center, Ehime University , Matsuyama , Ehime , Japan
| | - Tomoko Ishino
- b Division of Molecular Parasitology , Proteo-Science Center, Ehime University , Toon , Ehime , Japan
| | - Takafumi Tsuboi
- a Division of Malaria Research , Proteo-Science Center, Ehime University , Matsuyama , Ehime , Japan
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Minigo G, Flanagan KL, Slattery RM, Plebanski M. Vaccination with Altered Peptide Ligands of a Plasmodium berghei Circumsporozoite Protein CD8 T-Cell Epitope: A Model to Generate T Cells Resistant to Immune Interference by Polymorphic Epitopes. Front Immunol 2017; 8:115. [PMID: 28261200 PMCID: PMC5306364 DOI: 10.3389/fimmu.2017.00115] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2016] [Accepted: 01/25/2017] [Indexed: 11/13/2022] Open
Abstract
Many pathogens, including the malaria parasite Plasmodium falciparum, display high levels of polymorphism within T-cell epitope regions of proteins associated with protective immunity. The T-cell epitope variants are often non-cross-reactive. Herein, we show in a murine model, which modifies a protective CD8 T-cell epitope from the circumsporozoite protein (CS) of Plasmodium berghei (SYIPSAEKI), that simultaneous or sequential co-stimulation with two of its putative similarly non-cross-reactive altered peptide ligand (APL) epitopes (SYIPSAEDI or SYIPSAEAI) has radically different effects on immunity. Hence, co-immunization or sequential stimulation in vivo of SYIPSAEKI with its APL antagonist SYIPSAEDI decreases immunity to both epitopes. By contrast, co-immunization with SYIPSAEAI has no apparent initial effect, but it renders the immune response to SYIPSAEKI resistant to being turned off by subsequent immunization with SYIPSAEDI. These results suggest a novel strategy for vaccines that target polymorphic epitopes potentially capable of mutual immune interference in the field, by initiating an immune response by co-immunization with the desired index epitope, together with a carefully selected "potentiator" APL peptide.
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Affiliation(s)
- Gabriela Minigo
- Vaccine and Infectious Diseases Laboratory, Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia; Global and Tropical Health Division, Menzies School of Health Research, Charles Darwin University, Darwin, NT, Australia
| | - Katie L Flanagan
- Vaccine and Infectious Diseases Laboratory, Department of Immunology and Pathology, Monash University, Melbourne, VIC, Australia; School of Medicine, University of Tasmania, Hobart, TAS, Australia
| | - Robyn M Slattery
- Diabetes Laboratory, Department of Immunology and Pathology, Monash University , Melbourne, VIC , Australia
| | - Magdalena Plebanski
- Vaccine and Infectious Diseases Laboratory, Department of Immunology and Pathology, Monash University , Melbourne, VIC , Australia
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Plebanski M, Flanagan KL. The Economics of Malaria Vaccine Development. Trends Parasitol 2017; 33:154-156. [PMID: 28169112 DOI: 10.1016/j.pt.2017.01.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 01/09/2017] [Indexed: 11/19/2022]
Abstract
Vaccines that do not take a comprehensive endpoint view of the pathogen population they want to tackle early in their developmental process, may find it financially prohibitive to redesign them once they have progressed down a costly regulatory and human trial pathway. Specifically, the lead malaria vaccine candidate RTS,S has limited ability to tackle parasite polymorphism and may induce sex-specific nonspecific effects (NSEs).
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Affiliation(s)
- Magdalena Plebanski
- Vaccine and Infectious Diseases Unit, Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia; Division of Therapeutics, Monash Institute of Medical Engineering (MIME), Monash University, Melbourne, Victoria, Australia.
| | - Katie L Flanagan
- Vaccine and Infectious Diseases Unit, Department of Immunology and Pathology, Monash University, Melbourne, Victoria, Australia; School of Medicine, University of Tasmania, Hobart, Tasmania, Australia
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12
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Sedegah M, Peters B, Hollingdale MR, Ganeshan HD, Huang J, Farooq F, Belmonte MN, Belmonte AD, Limbach KJ, Diggs C, Soisson L, Chuang I, Villasante ED. Vaccine Strain-Specificity of Protective HLA-Restricted Class 1 P. falciparum Epitopes. PLoS One 2016; 11:e0163026. [PMID: 27695088 PMCID: PMC5047630 DOI: 10.1371/journal.pone.0163026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 09/01/2016] [Indexed: 11/19/2022] Open
Abstract
A DNA prime/adenovirus boost malaria vaccine encoding Plasmodium falciparum strain 3D7 CSP and AMA1 elicited sterile clinical protection associated with CD8+ T cell interferon-gamma (IFN-γ) cells responses directed to HLA class 1-restricted AMA1 epitopes of the vaccine strain 3D7. Since a highly effective malaria vaccine must be broadly protective against multiple P. falciparum strains, we compared these AMA1 epitopes of two P. falciparum strains (7G8 and 3D7), which differ by single amino acid substitutions, in their ability to recall CD8+ T cell activities using ELISpot and flow cytometry/intracellular staining assays. The 7G8 variant peptides did not recall 3D7 vaccine-induced CD8+ T IFN-γ cell responses in these assays, suggesting that protection may be limited to the vaccine strain. The predicted MHC binding affinities of the 7G8 variant epitopes were similar to the 3D7 epitopes, suggesting that the amino acid substitutions of the 7G8 variants may have interfered with TCR recognition of the MHC:peptide complex or that the 7G8 variant may have acted as an altered peptide ligand. These results stress the importance of functional assays in defining protective epitopes. Clinical Trials Registrations: NCT00870987, NCT00392015
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Affiliation(s)
- Martha Sedegah
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, 20910, United States of America
| | - Bjoern Peters
- La Jolla Institute for Allergy and Immunology, La Jolla, CA, 92037, United States of America
| | - Michael R. Hollingdale
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, 20910, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD, 20817, United States of America
- * E-mail:
| | - Harini D. Ganeshan
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, 20910, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD, 20817, United States of America
| | - Jun Huang
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, 20910, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD, 20817, United States of America
| | - Fouzia Farooq
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, 20910, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD, 20817, United States of America
| | - Maria N. Belmonte
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, 20910, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD, 20817, United States of America
| | - Arnel D. Belmonte
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, 20910, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD, 20817, United States of America
| | - Keith J. Limbach
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, 20910, United States of America
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Rockville, MD, 20817, United States of America
| | - Carter Diggs
- USAID, Washington, DC, 20523, United States of America
| | | | - Ilin Chuang
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, 20910, United States of America
| | - Eileen D. Villasante
- Malaria Department, Naval Medical Research Center, Silver Spring, MD, 20910, United States of America
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Hollingdale MR, Sedegah M, Limbach K. Development of replication-deficient adenovirus malaria vaccines. Expert Rev Vaccines 2016; 16:261-271. [PMID: 27606709 DOI: 10.1080/14760584.2016.1228454] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
INTRODUCTION Malaria remains a major threat to endemic populations and travelers, including military personnel to these areas. A malaria vaccine is feasible, as radiation attenuated sporozoites induce nearly 100% efficacy. Areas covered: This review covers current malaria clinical trials using adenoviruses and pre-clinical research. Heterologous prime-boost regimens, including replication-deficient human adenovirus 5 (HuAd5) carrying malaria antigens, are efficacious. However, efficacy appears to be adversely affected by pre-existing anti-HuAd5 antibodies. Current strategies focus on replacing HuAd5 with rarer human adenoviruses or adenoviruses isolated from non-human primates (NHPs). The chimpanzee adenovirus ChAd63 is undergoing evaluation in clinical trials including infants in malaria-endemic areas. Key antigens have been identified and are being used alone, in combination, or with protein subunit vaccines. Gorilla adenoviruses carrying malaria antigens are also currently being evaluated in preclinical models. These replacement adenovirus vectors will be successfully used to develop vaccines against malaria, as well as other infectious diseases. Expert commentary: Simplified prime-boost single shot regimens, dry-coated live vector vaccines or silicon microneedle arrays could be developed for malaria or other vaccines. Replacement vectors with similar or superior immunogenicity have rapidly advanced, and several are now in extensive Phase 2 and beyond in malaria as well as other diseases, notably Ebola.
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Affiliation(s)
| | - Martha Sedegah
- a Malaria Department , Naval Medical Research Center , Silver Spring , MD , USA
| | - Keith Limbach
- a Malaria Department , Naval Medical Research Center , Silver Spring , MD , USA
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